Add inching settings for Sonoff POWR2

[msemenkin]

Summary

• expose the existing PULSE and XPulseWidth entities for Sonoff POWR2 devices with UIID 32
• declare the pulse width as a duration measured in seconds
• add coverage for the new entities to the existing POWR2 test

Background

UIID 32 devices report the pulse and pulseWidth parameters, but the SonoffLAN device specification does not include the existing entities that expose them.

As a result, Home Assistant receives the inching configuration but does not show it on the device page.

The pulse-width entity already converts the device value from milliseconds to seconds. This change adds the corresponding Home Assistant duration metadata and unit of measurement.

Both entities remain disabled by default, consistent with the existing inching entities used by other supported device types.

Testing

• 94 tests passed
• tested with Home Assistant 2026.7.4 and Python 3.14.6
• manually verified on a PSF-X67 device with UIID 32